China’s Giant Salamanders are gone from the wild

The Chinese Giant Salamander, Andrias davidianus (Blanchard, 1871), is the largest amphibians living today and may exceed more than one metre in length. It is widespread in central, south-western and southern China, although its range is now very fragmented. It occurs from 100–1,500 m ASL. Old records of the species in Taiwan may be the result of introductions from the mainland. Andrias davidianus inhabits large hill streams, usually in forested areas. Females lay approximately 500 eggs in a string in an submerged burrow or cavity that is occupied by a male. Eggs are fertilized externally and are guarded by the male during the 50-60 day incubation period. Larvae then develop in the streams, they use their reserve of yolk for the first month or so, before they start to feed. Over-exploitation for human consumption is the main threat to this species although habitat destruction, mostly from the construction of dams, but also water pollution from mining operations has been a serious problem. Although the species is commercially farmed, most in trade are likely taken from the wild. In 2013,  Turvey and his colleagues organized a nationwide giant salamander search — apparently the largest wildlife survey ever conducted in China. They spent three years scanning riverbeds and turning over rocks at 97 sites in 16 provinces. They found giant salamanders at just four of the sites. All of the animals had genetic profiles that did not match the places in which they were living, indicating they likely originated on farms. The researchers also interviewed nearly 3,000 local people, about half of whom said they had seen giant salamanders in the wild. But the most recent sightings they could recall took place, on average, 18 years ago. “There could be remnant populations of genuine salamanders scattered here and there, but they are effectively impossible for any researchers to find now,” Turvey said. Most of the animals now are found on farms in China. Giant salamanders released recently into the wild are genetically distinct from those that evolved there, a man-made “species.”


References

Liang Gang, Geng Baorong, Zhao Ermi. 2004. Andrias davidianus. The IUCN Red List of Threatened Species 2004: e.T1272A3375181.

Nuwer R. 2018. China’s Giant Salamanders Pose a Conservation Conundrum. NYT June 6, 2018.

Turvey ST, Chen S, Tapley B, Wei G, Xie F, Yan F, Yang J, Liang Z, Tian H, Wu M, Okada S. 2018. Imminent extinction in the wild of the world’s largest amphibian. Current Biology.28(10):R592-4.

Comments

Popular Posts